As carbon nanotube (CNT) applications become more abundant, so do production demands. Because of this increased activity, much research has been performed in examining the toxicity of CNTs. Nanotubes have been found to exhibit toxic effects to the body including inflammation, oxidative stress, and apoptosis, similar to that witnessed from asbestos. As such, an effective method to remove these toxic fibers from the environment needs to be developed. We hypothesize here that by using enzymatic catalysis, we can initiate degradation of CNTs in environmentally and physiologically relevant settings. Our preliminary data shows that a natural enzyme horseradish peroxidase (HRP), along with low, local concentrations of H2O2 (40 5M), can degrade these nanomaterials. We have also observed that human myeloperoxidase (hMPO) can degrade CNTs, illustrating a two-pronged approach (environment and human health). Our specific goals for this project include (1) identifying environmental and structural factors affecting the kinetics of CNT degradation using HRP and hMPO, (2) identifying the molecular mechanism(s) of CNT degradation catalyzed by HRP and hMPO, (3) determining the products of HRP/hMPO- degradation of CNTs and evaluating their toxicity. The significant endpoint of this study will be marked by an understanding of the effects of CNTs and their transformation products on human health, including the necessary chemical functionalization for their biodegradation in the environment and in vivo.

Public Health Relevance

Developments in nanotechnology vastly increase the demand and use of carbon nanotubes, correspondingly with their health hazards and toxicity to the environment. This dictates the necessity to develop approaches for safe removal of carbon nanotubes from the environment. This proposal outlines novel technologies and protocols for biodegradation of carbon nanotubes through enzymatic catalysis mitigating environmental and subsequent physiological toxicity from carbon nanomaterials.